It is known in connection with water pumps to use a pre-assembled integrated shaft bearing which is installed in a water pump housing, along with a separate mechanical seal that is installed to isolate the bearing from the engine coolant fluid on the impeller side of the shaft. In some cases, coolant leakage through the mechanical seal is purposely used to lubricate the mechanical seal faces. However, this coolant leakage can create condensate on the bearing seal lip areas. The condensate as well as any excess leakage of coolant through the mechanical seal raises the risk of condensate and/or coolant intrusion into the bearing, resulting in early bearing failure. Also, excessive grease leakage from the bearing in the region of the seal can block the condensate leakage vent hole resulting in a pressure build-up in the space between the mechanical seal and the bearing, which can also result in coolant intrusion into the bearing and early bearing failure.
It would be desirable to provide a water pump in which the known arrangements are improved to prevent early bearing failure due to these potential leakage issues.